How a detachable works

[IceEidolon]

a normal detach still has constant momentum, since for every time a chair slows down another accelerates so I guess the two chairs balance out leaving the motor with just the skier to accelerate.

I'm not experienced enough in this area to say anything for certain. My impression is high speed lifts have larger main drive motors than equally sized fixed grips, and I'll bow out of this one as quietly as I can since I lack any extra information (and I'm almost out of guesses).

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[Newpylong]

Yes that is correct. Double the HP of fixed grip in most cases.

 

[mister moose]

That's assuming you don't have to start or stop the lift, which (especially for lifts that serve beginner terrain) is not the case. High speed lifts have a few hundred extra FPS to add to the haul rope. Not to mention accelerating a couple hundred pounds of skier and chair every six seconds during normal operation.

True, starting and stopping consumes energy. Extra FPS requires no additional energy itself* except added frictional losses. Accelerating masses to the line speed takes energy, but nowhere near as much as you may think.

The difference in line speed between a fixed and a detach is about 600 FPM, or 10 FPS. Accelerating a mass to 10 FPS is the same energy as lifting that same mass a whole foot and a half. Not really much of a factor when the lift is humping you up 1,500 vertical feet or so. That's a thousand times more. There must be a lot of frictional losses in the whole detach rubber tire mechanism, but I'm still left thinking the larger motors are oversized for surge loads and long motor life. It sure isn't an indication of running load.

*Unless uphill capacity changes. As I said previously, butts up hill (per hour) and vertical rise are determining factors.

 

[Jully]

a normal detach still has constant momentum, since for every time a chair slows down another accelerates so I guess the two chairs balance out leaving the motor with just the skier to accelerate.

In an ideal world, sure, but there is an enormous amount of energy lost when that chair decelerates. The two chairs very much do not balance out. An HSQ's terminal is not a closed system by any stretch of the imagination even without thinking about skiers added.

 

[SIKSKIER]

I found this FWIW.


Administrator I
2,675 Posts:


Posted 19 April 2004 - 07:44 PM

OK, here's an example... Our Motherlode chair used $3558 of power for a 33 day period. This lift is a 400hp triple chair with 711m vertical and 1884m for slope length. For this month we used 34320 kWh. Our rates are a bit funny and seem to change, here's the breakdown:

4363.64 kWh @ $0.06096/kWh
14356.36 kWh @ $0.04629/kWh
3636.36 kWh @ $0.0637
11963.64 kWh @ $0.04837

There's also some other charges such as:
Billed Demand 161.74 kVA @ $4.53/kVA
Billed Demand 134.78 kVA @ $4.73/kVA

I think there was a rate change in the billing period, which would explain a couple things.